Degree of Hydrolysis Regulated by Enzyme Mediation of Wheat Gluten Fibrillation: Structural Characterization and Analysis of the Mechanism of Action.

The impact of different degrees of hydrolysis (DHs) on fibrillation when trypsin mediates wheat gluten (WG) fibrillation has not been thoroughly investigated. This study discussed the differences in amyloid fibrils (AFs) formed from wheat gluten peptides (WGPs) at various DH values. The results from Thioflavin T (ThT) fluorescence analysis indicated that WGPs with DH6 were able to form the most AFs. Changes in Fourier Transform Infrared (FTIR) absorption spectra and secondary structure also suggested a higher degree of fibrillation in DH6 WGPs. Analysis of surface hydrophobicity and ζ-potential showed that DH6 AFs had the highest surface hydrophobicity and the most stable water solutions. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) images revealed the best overall morphology of DH6 AFs. These findings can offer valuable insights into the development of a standardized method for preparing wheat gluten amyloid fibrils.

A Multifrequency Brain Network-Based Deep Learning Framework for Motor Imagery Decoding.

Motor imagery (MI) is an important part of brain-computer interface (BCI) research, which could decode the subject's intention and help remodel the neural system of stroke patients. Therefore, accurate decoding of electroencephalography- (EEG-) based motion imagination has received a lot of attention, especially in the research of rehabilitation training. We propose a novel multifrequency brain network-based deep learning framework for motor imagery decoding. Firstly, a multifrequency brain network is constructed from the multichannel MI-related EEG signals, and each layer corresponds to a specific brain frequency band. The structure of the multifrequency brain network matches the activity profile of the brain properly, which combines the information of channel and multifrequency. The filter bank common spatial pattern (FBCSP) algorithm filters the MI-based EEG signals in the spatial domain to extract features. Further, a multilayer convolutional network model is designed to distinguish different MI tasks accurately, which allows extracting and exploiting the topology in the multifrequency brain network. We use the public BCI competition IV dataset 2a and the public BCI competition III dataset IIIa to evaluate our framework and get state-of-the-art results in the first dataset, i.e., the average accuracy is 83.83% and the value of kappa is 0.784 for the BCI competition IV dataset 2a, and the accuracy is 89.45% and the value of kappa is 0.859 for the BCI competition III dataset IIIa. All these results demonstrate that our framework can classify different MI tasks from multichannel EEG signals effectively and show great potential in the study of remodelling the neural system of stroke patients.

Enhancement of phytochemical content and drying efficiency of onions (Allium cepa L.) through blanching.

BACKGROUND: This study investigated the effect of blanching (60, 70 and 80 °C for 1, 3, 5 and 10 min) combined with oven drying at 60 °C on the phenolic compounds, antioxidant activity, colour and drying characteristics (drying time, drying rate constant, effective moisture diffusivity and activation energy) of onion slices. RESULTS: Blanching of onion slices at 60 °C for 3 min and at 70 °C for 1 min prior to drying increased their bioactive compounds and antioxidant activity compared to the control samples and other treatments. Eighteen drying models were evaluated. The Modified Page and two-term exponential models best represented the drying data. The effective diffusivity ranged from 3.32 × 10-11 m2 s-1 (control) to 5.27 × 10-11 m2 s-1 , 5.01 × 10-11 m2 s-1 , and 4.74 × 10-11 m2 s-1 for onions blanched at 60 °C, 70 °C and 80 °C, respectively. The higher activation energy was observed for the control (unblanched) sample and slightly lower values were found for 1 min- and 3 min-blanched samples, confirming the higher drying efficiency as a result of the blanching pre-treatment. CONCLUSION: The use of blanching as a pre-treatment before drying of onions resulted in enhanced phytochemical content and drying efficiency. © 2017 Society of Chemical Industry.

Evaluation of polyphenolic content and antioxidant activity in two onion varieties grown under organic and conventional production systems.

BACKGROUND: Onions contain a number of bioactive compounds, in particular polyphenols. They are rich sources of such compounds in the human diet and offer significant health benefits to the consumer. Demand for organic crops is steadily increasing partly based on the expected health benefits of organic food consumption. The current study examines the influence of organic and conventional crop management practices on bioactive polyphenolic content of onion. RESULTS: We examined the effect of conventional, organic, and mixed cultivation practices on the content of total phenolics, total flavonoids and antioxidant activity in two varieties of onion grown over 4 years in a split-plot factorial systems comparison trial. Levels of total phenolics and total flavonoids showed a significant year-on-year variation and were significantly different between organic and conventional production systems. The levels of total phenolics, total flavonoids and antioxidant activity in general were significantly higher (P < 0.05) under fully organic compared to fully conventional management. CONCLUSION: Organic cultivation practices resulted in significantly higher levels of potential bioactive compounds in onion. © 2016 Society of Chemical Industry.

Multidimensional biological activities of resveratrol and its prospects and challenges in the health field.

Resveratrol (RES) is a naturally occurring polyphenolic compound. Recent studies have identified multiple potential health benefits of RES, including antioxidant, anti-inflammatory, anti-obesity, anticancer, anti-diabetic, cardiovascular, and neuroprotective properties. The objective of this review is to summarize and analyze the studies on the biological activities of RES in disease prevention and treatment, as well as its metabolism and bioavailability. It also discusses the challenges in its clinical application and future research directions. RES exhibits significant potential in the prevention and treatment of many diseases. The future direction of RES research should focus on improving its bioavailability, conducting more clinical trials to determine its effectiveness in humans, and investigating its mechanism of action. Once these challenges have been overcome, RES is expected to become an effective health intervention.

Formation, structural characteristics and specific peptide identification of gluten amyloid fibrils.

This research investigates the formation of amyloid fibrils using enzymatically hydrolyzed peptides from gluten, including its components glutenin and gliadin. After completing the fibrillation incubation, the gluten group demonstrated the most significant average particle size (908.67 nm) and conversion ratio (57.64 %), with a 19.21 % increase in thioflavin T fluorescence intensity due to self-assembly. The results indicated increased levels of ß-sheet structures after fibrillation. The gliadin group exhibited the highest zeta potential (∼13 mV) and surface hydrophobicity (H0 = 809.70). Around 71.15 % of predicted amyloidogenic regions within gliadin peptides showed heightened hydrophobicity. These findings emphasize the collaborative influence of both glutenin and gliadin in the formation of gluten fibrils, influenced by hydrogen bonding, hydrophobic, and electrostatic interactions. They also highlight the crucial role played by gliadin with amyloidogenic fragments such as ILQQIL and SLVLQTL, aiming to provide a theoretical basis for understanding the utilization of gluten proteins.

Formation and Application of Starch-Polyphenol Complexes: Influencing Factors and Rapid Screening Based on Chemometrics.

Understanding the nuanced interplay between plant polyphenols and starch could have significant implications. For example, it could lead to the development of tailor-made starches for specific applications, from bakinag and brewing to pharmaceuticals and bioplastics. In addition, this knowledge could contribute to the formulation of functional foods with lower glycemic indexes or improved nutrient delivery. Variations in the complexes can be attributed to differences in molecular weight, structure, and even the content of the polyphenols. In addition, the unique structural characteristics of starches, such as amylose/amylopectin ratio and crystalline density, also contribute to the observed effects. Processing conditions and methods will always alter the formation of complexes. As the type of starch/polyphenol can have a significant impact on the formation of the complex, the selection of suitable botanical sources of starch/polyphenols has become a focus. Spectroscopy coupled with chemometrics is a convenient and accurate method for rapidly identifying starches/polyphenols and screening for the desired botanical source. Understanding these relationships is crucial for optimizing starch-based systems in various applications, from food technology to pharmaceutical formulations.

Investigating the impact of ultrasound-assisted cellulase pretreatment on the nutrients, phytic acid, and phenolics bioaccessibility in sprouted brown rice.

This study aimed to elucidate the impact of ultrasound-assisted cellulase (UC) pretreatment on nutrients, phytic acid, and the bioavailability of phenolics during brown rice sprouting. It sought to unveil the underlying mechanisms by quantifying the activity of key enzymes implicated in these processes. The sprouted brown rice (SBR) surface structure was harmed by the UC pretreatment, which also increased the amount of γ-oryzanol and antioxidant activity in the SBR. Concurrently, the UC pretreatment boosted the activity of phytase, glutamate decarboxylase, succinate semialdehyde dehydrogenase, Gamma-aminobutyric acid (GABA) transaminase, chalcone isomerase, and phenylalanine ammonia lyase, thereby decreasing the phytic acid content and increasing the GABA, flavonoid, and phenolic content in SBR. In addition, UC-pretreated SBR showed increased phenolic release and bioaccessibility during in vitro digestion when compared to the treated group. These findings might offer theoretical direction for using SBR to maximize value.

Effect of hydrocolloids on gluten proteins, dough, and flour products: A review.

Hydrocolloids are among the most common components in the food industry, which are used for thickening, gel formation, emulsification, and stabilization. Previous studies have also found that hydrocolloids can affect the structures and properties of gluten proteins, dough, and flour products. In this review, hydrocolloids were separated into three categories: anionic, nonionic, and other hydrocolloids, and reviewed the effects of common hydrocolloids on gluten proteins, dough, and flour products. Hydrocolloids can affect the structures and properties of gluten proteins through gluten-hydrocolloids interaction, secondary structures, disulfide bonds, environment of aromatic amino acids, and chemical bonds. The properties of dough are affected by rheological, fermentation, and thermomechanical properties. Hydrocolloids are widely used in bread, Chinese steamed bread, noodles, yellow layer cake, and so on, which mainly affect their appearance, texture, and aging speed. This comprehensive review provides a scientific guide for the development and utilization of hydrocolloids and their applications in flour products, and provides a theoretical basis for improving the processing characteristics of products.

Preparation and Characterization of Ferulic Acid Wheat Gluten Nanofiber Films with Excellent Antimicrobial Properties.

In this study, composite nanofiber films comprising polyvinyl alcohol, wheat gluten, and glucose (PWG) were fabricated using electrospinning, followed by crosslinking via Maillard crosslinking. Various mass concentrations of ferulic acid (FA) were incorporated into PWG films. The results indicated that the average diameter of the FA-PWG films decreased from 449 nm to 331 nm as the concentration of FA increased, until reaching a concentration of 12%; after which, a significant increase in diameter was observed. The subsequent Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC) results suggested that FA was distributed in the sample films in an amorphous form through hydrogen and ester bonds. Additionally, release experiments and antimicrobial tests on the FA-PWG sample films showed the good controlled release of FA and excellent anti-Escherichia coli and Staphylococcus aureus activity of this film. These findings all indicate that the FA-PWG nanofiber film is a potential candidate for active food packaging.

Wheat gluten amyloid fibrils: Conditions, mechanism, characterization, application, and future perspectives.

Amyloid fibrils have excellent structural characteristics, such as a high aspect ratio, excellent stiffness, and a wide availability of functional groups on the surface. More studies are now focusing on the formation of amyloid fibrils using food proteins. Protein fibrillation is now becoming recognized as a promising strategy for enhancing the function of food proteins and expanding their range of applications. Wheat gluten is rich in glutamine (Q), hydrophobic amino acids, and the α-helix structure with high ß-sheet tendency. These characteristics make it very easy for wheat gluten to form amyloid fibrils. The conditions, formation mechanism, characterization methods, and application of amyloid fibrils formed by wheat gluten are summarized in this review. Further exploration of amyloid fibrils formed by wheat gluten will reveal how they can play a significant role in food, biology, and other fields, especially in medicine.

Molecular Mechanisms and Applications of Polyphenol-Protein Complexes with Antioxidant Properties: A Review.

Proteins have been extensively studied for their outstanding functional properties, while polyphenols have been shown to possess biological activities such as antioxidant properties. There is increasing clarity about the enhanced functional properties as well as the potential application prospects for the polyphenol-protein complexes with antioxidant properties. It is both a means of protein modification to provide enhanced antioxidant capacity and a way to deliver or protect polyphenols from degradation. This review shows that polyphenol-protein complexes could be formed via non-covalent or covalent interactions. The methods to assess the complex's antioxidant capacity, including scavenging free radicals and preventing lipid peroxidation, are summarized. The combination mode, the type of protein or polyphenol, and the external conditions will be the factors affecting the antioxidant properties of the complexes. There are several food systems that can benefit from the enhanced antioxidant properties of polyphenol-protein complexes, including emulsions, gels, packaging films, and bioactive substance delivery systems. Further validation of the cellular and in vivo safety of the complexes and further expansion of the types and sources of proteins and polyphenols for forming complexes are urgently needed to be addressed. The review will provide effective information for expanding applications of proteins and polyphenols in the food industry.

Study on electrospinning of wheat gluten: A review.

Electrospinning has attracted extensive attention among various nanofabrication technologies owing to its ability to produce nanofiber structures with unique properties, such as high specific surface area and porosity, as well as tunable fiber morphology and mechanical properties. The most representative spinning raw materials include natural polymers and synthetic polymers. Owing to the sustainable development strategies, more and more researchers focus on natural polymers. Among natural polymers, wheat gluten (WG) nanofibers have recently attracted much attention owing to its high specific surface area, superior biocompatibility, and unique viscoelasticity. This review summarizes the composition and characteristics of WG, the physical and chemical indicators of a WG electrospinning solution, the main influencing factors in the WG electrospinning process and a characterizations of WG nanofibers. Finally, the review also outlines the applications of WG nanofibers in drug release, biological scaffold, and active food packaging.

Plant bioactive compounds alleviate photoinduced retinal damage and asthenopia: Mechanisms, synergies, and bioavailability.

The retina, an important tissue of the eye, is essential in visual transmission and sustaining adequate eyesight. However, oxidative stress and inflammatory reactions can harm retinal structure and function. Recent studies have demonstrated that exposure to light can induce oxidative stress and inflammatory reactions in retinal cells, thereby facilitating the progression of retinal damage-related diseases and asthenopia. Plant bioactive compounds such as anthocyanin, curcumin, resveratrol, lutein, zeaxanthin, epigallocatechin gallate, and quercetin are effective in alleviating retinal damage and asthenopia. Their strong oxidation resistance and unique chemical structure can prevent the retina from producing reactive oxygen species and regulating eye muscle relaxation, thus alleviating retinal damage and asthenopia. Additionally, the combination of these active ingredients produces a stronger antioxidant effect. Consequently, understanding the mechanism of retinal damage caused by light and the regulation mechanism of bioactive compounds can better protect the retina and reduce asthenopia.

Effects of Different Processing Methods and Internal Components on Physicochemical Properties and Glycemic Index of Adzuki Bean Powder.

The estimated glycemic index (eGI) value of adzuki bean powder prepared by steamed cooking (SC), extruded cooking (EC) and roller cooking (RC) was studied comparatively. Results showed that RC had the highest eGI, with 80.1, and both EC and SC resulted in a lower eGI value of 70.0 and 49.7, respectively. Compared with the EC and RC methods, the SC method provided a more intact physical barrier for starch digestion, resulting in a less destroyed cell structure. As the essential components that form the cell wall, the study further investigated the effects of protein and fiber on physicochemical properties, in vitro starch digestibility and the eGI of adzuki bean powder processed with the SC method. Viscozyme and Protamax were used to obtain the deprotein and defiber samples. Results showed that the SC treatment with Viscozyme and Protamax, respectively, had significant effects on in vitro starch digestibility. The eGI of different samples were given as follows: steamed cooking adzuki bean powder (49.7) < deproteined adzuki bean powder (60.5) < defibered adzuki bean powder (83.1), which indicates that fiber may have a greater influence on the eGI than protein.

Effect of storage, food processing and novel extraction technologies on onions flavonoid content: A review.

Onions play an important part in the daily diet for most populations around the world owing to their nutritional composition and their unique capacity to naturally flavor dishes. Onions contain quercetin and its derivatives - the predominant flavonoid in onions that exert a great contribution to the effective bioactive properties of onion, including its derived products. The present paper comprehensively reviewed flavonoids (with a specific focus on quercetin in onions): their chemical composition, distribution, bioactivities in onion, and impacting factors with a focus on how they can be affected by various post-harvest conditions (storage and food processing). In addition, research on the extraction of flavonoid compounds from onions using a number of novel technologies was also reviewed.

Higher Antioxidant Activity, Total Flavonols, and Specific Quercetin Glucosides in Two Different Onion (Allium cepa L.) Varieties Grown under Organic Production: Results from a 6-Year Field Study.

We carried out a 6-year study to assess the effect of conventional, organic, and mixed cultivation practices on bioactive compounds (flavonoids, anthocyanins) and antioxidant capacity in onion. Total flavonoids, total anthocyanins, individual flavonols, individual anthocyanins, and antioxidant activity were measured in two varieties ('Hyskin' and 'Red Baron') grown in a long-term split-plot factorial systems comparison trial. This is the first report of repeated measurements of bioactive content over an extensive time period in a single crop type within the same trial. Antioxidant activity (DPPH and FRAP), total flavonol content, and levels of Q 3,4' D and Q 3 G were higher in both varieties under fully organic compared to fully conventional management. Total flavonoids were higher in 'Red Baron' and when onions were grown under organic soil treatment. Differences were primarily due to different soil management practices used in organic agriculture rather than pesticide/ herbicide application.